Most telephone operating companies have been offering calling line identification services in which the information of a calling party's telephone number and/or name is sent from a local central office to the called party's telephone station apparatus if a called party is a subscriber of that service. Early proposed versions of this service may be found in U.S. Pat. Nos. 3,727,003 and 3,812,296 to Paraskevakos, as well as in U.S. Pat. No. 3,787,626 to Subieta. A more recent scheme for providing this service is discussed in U.S. Pat. No. Re. 31,789 to Hashimoto.
In these patents, the directory number of a calling party is coded as FSK modulated pulse trains and is transmitted from the originating central office to the terminating office and sent to the called party's telephone station apparatus either before an alerting signal such as ringing is sent or during a silent interval between ringing signals. In these patents, the called party's station apparatus must be equipped with receiving circuitry for decoding the FSK modulated digital signal as well as a display device to indicate the identity of the calling party. The called party is then placed in the position of being given the opportunity to answer the call or ignore it. U.S. Pat. No. 5,263,084 to Chaput et al., discloses a method and a telephone station apparatus of displaying an identification of a third calling party.
Such visible identification of the calling party's telephone number or name is not advantageous for vision impaired people nor is visible identification convenient for identifying the calling party in the case where the called party is away from the telephone station apparatus which displays a calling party's telephone number in an onhook condition. Various schemes, therefore, have been proposed for providing audible annunciation of the calling party. One such scheme is disclosed in U.S. Pat. No. 4,922,490 to Blakely, however, this scheme involves interpretation of the calling party's identification at a central office switch and transmission of audio information directly to a telephone, the telephone being equipped with audio annunciation apparatus for producing an audio annunciation based on the audio signal provided by the central office. This renders the quality of the audio heard by the user dependent upon the audio production equipment at the central office. In addition, Magnovox has a website on the Internet at http://www.esn.net/callerid/TCmore.html which describes a voice announced caller identification unit. However, there is no indication that this device cooperates with text to speech converter or an external database to produce good quality audio. The present invention addresses this need.
The use of CLID information directly as it is provided by the telephone switch does not necessarily convert into a meaningful result when applied to a text to speech converter. For example, if the subscriber lists his name as T. A. Kuechler, the initials T. A. K may be treated as the word or syllable "tak". This may defeat the purpose of audibly announcing the caller's name as the name cannot be readily recognized as that of Mr. Kuechler. What would be desirable, therefore, is a device which would apply some intelligence to the information received as Caller Identification Information to provide an optimum audible announcement of the identity of the calling party.